Financed a $19,500 car at 6.2%. This loan will cost me $4k. Should I sell some investments to pay off in full? Or maybe half? Or just pay the loan?

I have no other debts, and can probably afford to waste the $4k. I have a safe well paying job at 108k a year, and an emergency fund in cash.

Planning to retire in 18 or so years. Probably going to rent forever